Method for detecting methanol content in transformer insulation paper

Abstract

The invention discloses a method for detecting the content of methanol in transformer insulation paper, and the method comprises the following steps of: S1, adding 1mL of to-be-detected methanol into a 25mL colorimetric tube, sequentially transferring 2.5mL of a 25% sulfuric acid solution and 0.5mL of a potassium permanganate solution, uniformly shaking and standing the substances for 10min to obtain a first mixed solution; S2, dropwise adding a sodium sulfite solution into the first mixed solution obtained in the S1 until the color just fades, then dropwise adding two drops of chromotropic acid, uniformly mixing the substances, slowly transferring 6mL of concentrated sulfuric acid along the wall of a colorimetric tube, and uniformly mixing the substances; S3, performing standing and cooling to room temperature, adding water to dilute to a 25mL scale line, and uniformly mixing the substances to obtain a to-be-detected mixed solution; and S4, measuring 3mL of the to-be-detected mixed solution, putting the solution into a 10*10mm quartz cuvette, taking pure water as a reference solution, detecting the absorbance of the mixed solution by using a spectrograph, recording the spectrum of the mixed solution, and calculating the methanol concentration. Based on the spectrum principle, the methanol concentration is obtained according to the relation between the methanol concentration and the characteristic absorbance, the detection cost is reduced, and the detection accuracy is improved.

Description

Technical field[0001]The present invention relates to the field of insulating paper detection, and more particularly to a method of detecting methanol content in transformer insulating paper.Background technique[0002]The transformer is the core component in the power system. The grid requires the transformer to operate safely. The state of the transformer depends primarily on its insulation system, the insulation system of the transformer is mainly composed of insulating oil and insulated paper. Since the insulating paper is difficult to replace, the service life has directly determined the life of the transformer, so the fault diagnosis and life assessment of the transformer is mainly achieved by judging the aging state of the insulating paper. At present, there are two types of insulation paper aging assessment: 1) The degree of polymerization of the insulation paper. 2) Furfural in the transformer is a furan compound, which can be used as a feature product decomposed by insulatin...

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Problems solved by technology

[0003] However, the above two existing insulation paper aging evaluation methods have the following disadvantages: 1) The disadvantage of the degree of polymerization measurement is that it is easily affected by the sampling point, and the results obtained according to different sampling points may have large differences

In addition, since the measurement of the average degree of polymerization requires the transformer to be sampled from the suspension cover, the transformer will be taken out of operation, and the corresponding method is difficult to apply to on-site measurement

2) Disadvantages of furfural measurement, first, various factors such as insulating paper type, moisture, temperature, etc. will increase the dispersion of measurement results; in addition, many transformers are equipped with thermosiphon filters, built-in adsorbents, and a part of the convectively circulated oil Furfural is lost

In this case, it is necessary to perform compensation calculations on the measured values, and it is difficult to guarantee accurate results.

At the same time, the treatment measures that the transformer may undergo oil change after long-term operation should also be considered, which will cause a large part of furfural to be lost, resulting in measurement results that cannot reflect the real aging state

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